Dears, I have the same problem, but another one error: On my pre-production stand with one node in cluster, I was set hode to maintenance, and after try update cluster to 4.5 i see: Error while executing action: Cannot change Cluster compatibility version where there are no hosts in the Cluster which support that version. ENGINE LOG: 2020-12-11 15:48:26,338+02 INFO [org.ovirt.engine.core.bll.UpdateClusterCommand] (default task-1) [383d1f09-039d-4737-9e8d-9b2490717bd8] Updating cluster CPU flags and verb according to the configuration of the Intel Westmere Family cpu 2020-12-11 15:48:26,347+02 INFO [org.ovirt.engine.core.bll.UpdateClusterCommand] (default task-1) [383d1f09-039d-4737-9e8d-9b2490717bd8] Lock Acquired to object 'EngineLock:{exclusiveLocks='[]', sharedLocks='[9abc1d61-829e-470b-b6c8-ad5aec769869=VM]'}' 2020-12-11 15:48:26,389+02 WARN [org.ovirt.engine.core.bll.UpdateClusterCommand] (default task-1) [383d1f09-039d-4737-9e8d-9b2490717bd8] Validation of action 'UpdateCluster' failed for user smelnyk@internal-authz. Reasons: VAR__TYPE__CLUSTER,VAR__ACTION__UPDATE,CLUSTER_CANNOT_UPDATE_VERSION_WHEN_NO_HOST_SUPPORTS_THE_VERSION 2020-12-11 15:48:26,390+02 INFO [org.ovirt.engine.core.bll.UpdateClusterCommand] (default task-1) [383d1f09-039d-4737-9e8d-9b2490717bd8] Lock freed to object 'EngineLock:{exclusiveLocks='[]', sharedLocks='[9abc1d61-829e-470b-b6c8-ad5aec769869=VM]'}' HOST: OS Version: RHEL - 8.3 - 1.2011.el8 OS Description: CentOS Linux 8 Kernel Version: 4.18.0 - 240.1.1.el8_3.x86_64 KVM Version: 4.2.0 - 34.module_el8.3.0+555+a55c8938 LIBVIRT Version: libvirt-6.0.0-28.module_el8.3.0+555+a55c8938 VDSM Version: vdsm-4.40.35.1-1.el8 SPICE Version: 0.14.3 - 3.el8 GlusterFS Version: [N/A] CEPH Version: librbd1-12.2.7-9.el8 Open vSwitch Version: [N/A] Nmstate Version: nmstate-0.3.6-2.el8 Kernel Features: MDS: (Vulnerable: Clear CPU buffers attempted, no microcode; SMT vulnerable), L1TF: (Mitigation: PTE Inversion; VMX: conditional cache flushes, SMT vulnerable), SRBDS: (Not affected), MELTDOWN: (Mitigation: PTI), SPECTRE_V1: (Mitigation: usercopy/swapgs barriers and __user pointer sanitization), SPECTRE_V2: (Mitigation: Full generic retpoline, IBPB: conditional, IBRS_FW, STIBP: conditional, RSB filling), ITLB_MULTIHIT: (KVM: Mitigation: Split huge pages), TSX_ASYNC_ABORT: (Not affected), SPEC_STORE_BYPASS: (Mitigation: Speculative Store Bypass disabled via prctl and seccomp) VNC Encryption: Disabled FIPS mode enabled: Disabled